sim2cm.c File Reference

Simulation of 2-tissue compartmental models. More...

#include "tpcclibConfig.h"
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>
#include <string.h>
#include "tpccm.h"

Go to the source code of this file.

Functions
int	simC2 (double *t, double *ca, const int nr, const double k1, const double k2, const double k3, const double k4, double *ct, double *cta, double *ctb)
int	simC2_i (double *t, double *cai, const int nr, const double k1, const double k2, const double k3, const double k4, double *ct, double *cta, double *ctb)

Detailed Description

Simulation of 2-tissue compartmental models.

Definition in file sim2cm.c.

Function Documentation

simC2()

int simC2	(	double *	t,
		double *	ca,
		const int	nr,
		const double	k1,
		const double	k2,
		const double	k3,
		const double	k4,
		double *	ct,
		double *	cta,
		double *	ctb )

Simulate tissue TAC using two-tissue compartment model and plasma TAC, at plasma TAC times.

Memory for ct must be allocated in the calling program. To retrieve the separate tissue compartment TACs, pointer to allocated memory for cta and/or ctb can be given; if compartmental TACs are not required, NULL pointer can be given instead.

The units of rate constants must be related to the time unit; 1/min and min, or 1/sec and sec.

Returns

Function returns 0 when successful, else a value >= 1.

Author

Vesa Oikonen

See also

simC2_i, simC1, simC1DI, simC2l, simC3s, simC3p, simSRTM, simSamples, simDispersion, parExampleTTACs, parExamplePerfectBolus

Parameters

t	Array of time values.
ca	Array of arterial activities.
nr	Number of values in TACs.
k1	Rate constant of the model.
k2	Rate constant of the model.
k3	Rate constant of the model.
k4	Rate constant of the model.
ct	Pointer for TAC array to be simulated; must be allocated.
cta	Pointer for 1st compartment TAC to be simulated, or NULL.
ctb	Pointer for 2nd compartment TAC to be simulated, or NULL.

Definition at line 31 of file sim2cm.c.

  {
  int i;
  double dt2, r, u, v;
  double cai, ca_last, t_last;
  double ct1, ct1_last, ct2, ct2_last;
  double ct1i, ct1i_last, ct2i, ct2i_last;
 
 
  /* Check for data */
  if(nr<2) return 1;
  if(t==NULL || ca==NULL || ct==NULL) return 2;
 
  /* Check parameters */
  if(k1<0.0) return 3;
 
  /* Calculate curves */
  t_last=0.0; if(t[0]<t_last) t_last=t[0];
  cai=ca_last=0.0;
  ct1_last=ct2_last=ct1i_last=ct2i_last=0.0;
  ct1=ct2=ct1i=ct2i=0.0;
  for(i=0; i<nr; i++) {
    /* delta time / 2 */
    dt2=0.5*(t[i]-t_last);
    /* calculate values */
    if(dt2<0.0) {
      return 5;
    } else if(dt2>0.0) {
      /* arterial integral */
      cai+=(ca[i]+ca_last)*dt2;
      /* Calculate partial results */
      r=1.0+k4*dt2;
      u=ct1i_last+dt2*ct1_last;
      v=ct2i_last+dt2*ct2_last;
      /* 1st tissue compartment and its integral */
      ct1 = ( k1*cai - (k2 + (k3/r))*u + (k4/r)*v ) / ( 1.0 + dt2*(k2 + (k3/r)) );
      ct1i = ct1i_last + dt2*(ct1_last+ct1);
      /* 2nd tissue compartment and its integral */
      ct2 = (k3*ct1i - k4*v) / r;
      ct2i = ct2i_last + dt2*(ct2_last+ct2);
    }
    /* copy values to argument arrays */
    ct[i]=ct1+ct2;
    if(cta!=NULL) cta[i]=ct1;
    if(ctb!=NULL) ctb[i]=ct2;
    /* prepare to the next loop */
    t_last=t[i]; ca_last=ca[i];
    ct1_last=ct1; ct1i_last=ct1i;
    ct2_last=ct2; ct2i_last=ct2i;
  }
 
  return 0;
}

simC2_i()

int simC2_i	(	double *	t,
		double *	cai,
		const int	nr,
		const double	k1,
		const double	k2,
		const double	k3,
		const double	k4,
		double *	ct,
		double *	cta,
		double *	ctb )

Simulate tissue TAC using two-tissue compartment model and plasma TAC, at plasma TAC times.

Memory for ct must be allocated in the calling program. To retrieve the separate tissue compartment TACs, pointer to allocated memory for cta and/or ctb can be given; if compartmental TACs are not required, NULL pointer can be given instead.

The units of rate constants must be related to the time unit; 1/min and min, or 1/sec and sec.

This version uses integral of arterial TAC as input function. Only advantage over simC2() is that the calculation of integral can be fully controlled and possibly more precise in some situations.

Returns

Function returns 0 when successful, else a value >= 1.

Author

Vesa Oikonen

See also

simC2, simC1, simC1_i, simC3s, simC3p, simSamples, simDelay

Parameters

t	Array of time values.
cai	Array of AUC 0-t of arterial activities.
nr	Number of values in TACs.
k1	Rate constant of the model.
k2	Rate constant of the model.
k3	Rate constant of the model.
k4	Rate constant of the model.
ct	Pointer for TAC array to be simulated; must be allocated.
cta	Pointer for 1st compartment TAC to be simulated, or NULL.
ctb	Pointer for 2nd compartment TAC to be simulated, or NULL.

Definition at line 124 of file sim2cm.c.

  {
  int i;
  double dt2, r, u, v;
  double t_last;
  double ct1, ct1_last, ct2, ct2_last;
  double ct1i, ct1i_last, ct2i, ct2i_last;
 
 
  /* Check for data */
  if(nr<2) return 1;
  if(t==NULL || cai==NULL || ct==NULL) return 2;
 
  /* Check parameters */
  if(k1<0.0) return 3;
 
  /* Calculate curves */
  t_last=0.0; if(t[0]<t_last) t_last=t[0];
  ct1_last=ct2_last=ct1i_last=ct2i_last=0.0;
  ct1=ct2=ct1i=ct2i=0.0;
  for(i=0; i<nr; i++) {
    /* delta time / 2 */
    dt2=0.5*(t[i]-t_last);
    /* calculate values */
    if(dt2<0.0) {
      return 5;
    } else if(dt2>0.0) {
      /* Calculate partial results */
      r=1.0+k4*dt2;
      u=ct1i_last+dt2*ct1_last;
      v=ct2i_last+dt2*ct2_last;
      /* 1st tissue compartment and its integral */
      ct1 = ( k1*cai[i] - (k2 + (k3/r))*u + (k4/r)*v ) / ( 1.0 + dt2*(k2 + (k3/r)) );
      ct1i = ct1i_last + dt2*(ct1_last+ct1);
      /* 2nd tissue compartment and its integral */
      ct2 = (k3*ct1i - k4*v) / r;
      ct2i = ct2i_last + dt2*(ct2_last+ct2);
    }
    /* copy values to argument arrays */
    ct[i]=ct1+ct2;
    if(cta!=NULL) cta[i]=ct1;
    if(ctb!=NULL) ctb[i]=ct2;
    /* prepare to the next loop */
    t_last=t[i];
    ct1_last=ct1; ct1i_last=ct1i;
    ct2_last=ct2; ct2i_last=ct2i;
  }
 
  return 0;
}